1. Field of the Invention
The invention relates to analytical sampling devices and, in particular, to centrifuge devices having one or more microwave energy sources for applying microwave energy to samples in the centrifuge devices.
2. State of the Art
Centrifuges are well known and are commonly used to assist with and perform analytical measurements in many different industries. Typically, centrifuges are used for separating mixtures including mixtures having constituents with different densities. Such devices provide methods for separating mixtures comprising at least two or more insoluble liquids or constituents from one another. For example, emulsions, which are a mixture of two or more immiscible liquids, may be separated using a centrifuge.
In the oil and gas industries, continuous feed centrifuges may be used to separate emulsions of oil and water or emulsions including oil, water, and solids. For example, U.S. Pat. No. 7,150,836, issued Dec. 19, 2006, entitled “MICROWAVE-EMITTING ROTOR, SEPARATOR APPARATUS INCLUDING SAME, METHODS OF OPERATION AND DESIGN THEREOF” is incorporated in its entirety herein by reference and describes various centrifuges and methods of using centrifuges to separate oil and water emulsions before and during crude oil refining processes.
Oil refining processes typically require that the amounts of water, solids, and other impurities accompanying crude oil delivered to a refining process are at or below a standard amount, for example, at about one percent. If water, solids, or other impurities in the crude oil exceed the processing limitations, damage to the refining equipment or the pipeline equipment that delivers the crude to the refinery may occur. For instance, excess amounts of water and solids in crude oil being piped to a refinery may accelerate corrosion of the pipeline. Such damage is unwanted.
In an attempt to determine the amount of impurities and undesired constituents in crude oil prior to refinement or prior to feed to a continuous centrifuge, the crude oil may be tested at the well-head or platform where the crude oil is drawn from the well. Such testing is routinely carried out and is often performed using a SETA Oil Test Centrifuge. SETA Oil Test Centrifuges are the only testing equipment currently certified to meet or exceed the ASTM (American Society of Testing and Materials) and API (American Petroleum Institute) requirements for crude oil testing.
SETA Oil Test Centrifuges generally include a swinging bucket rotor having four sample placement buckets encased in a thermally heated chamber having a closable lid. The thermally heated chamber and rotor are contained within a shell that also encloses a drive mechanism, microprocessor unit, and controls for setting, monitoring, and controlling sample runs using the SETA Oil Test Centrifuge.
Operation of the SETA Oil Test Centrifuge can be expensive. In addition, thermal heating of the samples takes time. The amount of time required to thermally heat samples being tested in a SETA Oil Test Centrifuge limits the number of samples that may be obtained and analyzed in any given period of time. In many instances, the samples being tested in a SETA Oil Test Centrifuge must also be diluted with solvents to lighten the samples and to speed up or facilitate the sampling process. The addition of solvents to the samples adds to the cost of the sampling, increases the amount of waste produced by the sampling, and can increase the safety hazards associated with the testing due to the transport and heating of solvents.
Therefore, it would be desirable to provide centrifuge testing devices and methods having improved heating capabilities. It would also be desirable to provide centrifuge testing devices that could be used to facilitate improved testing of crude oil and especially the testing of crude oil at well heads and on oil platforms and, in at least some instances, testing of oil samples without solvents.